Accession Number : ADA331865

Title :   Computation of the 3-D Unsteady Flow Past Deforming Geometries

Corporate Author : NAVAL RESEARCH LAB WASHINGTON DC CENTER FOR REACTIVE FLOW AND DYNAMICAL SYSTEMS

Personal Author(s) : Ramamurti, Ravi ; Sandberg, William C. ; Lohner, Rainald

PDF Url : ADA331865

Report Date : 20 OCT 1997

Pagination or Media Count : 24

Abstract : A 3-D incompressible unsteady flow solver based on simple finite elements with adaptive remeshing and grid movement for both moving and deforming surfaces is described. We demonstrate the combination of adaptive remeshing technique with the incompressible flow solver by computing the flow past an undulating eel in 2-D and past a swimming bluefin tuna in 3-D. It is clear that proper choice of the amplitude and frequency of undulation is necessary for positive thrust production in the eel. Unsteady flow of the swimming tuna with caudal fin oscillation and quasi-steady state flow at several caudal fin positions are computed. Comparison of these results show that the unsteady flow is considerably different in both magnitude and trend suggesting that unsteady flow about moving deforming bodies is not amenable to spatial decomposition or temporal, quasi-steady approximations.

Descriptors :   *UNSTEADY FLOW, *INCOMPRESSIBLE FLOW, FINITE ELEMENT ANALYSIS, DEFORMATION, COMPUTATIONAL FLUID DYNAMICS, FLOW FIELDS, HYDRODYNAMIC CODES, PRESSURE DISTRIBUTION, THREE DIMENSIONAL FLOW, TUNA.

Subject Categories : Fluid Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE